It is desirable to incorporate hydrophobic polyolefin components into acrylic polymers and acrylic networks to enhance the hydrophobicity of the acrylics, to lower their water uptake, to improve the crosslink stability of acrylic coatings and particles, to impact mechanical toughness, and to raise surface hydrophobicity. One approach to achieve these ends is to use C18-C22 fatty acid derivatives as di-acid chain extenders. However, the hydrophobicity of acrylics can only be raised slightly in this manner due to the short alkyl length while the crosslink density is reduced. Another method is to incorporate polyolefin latex into the acrylic coating formulation. However, those polyolefin latexes have been prepared by grinding polyolefin pellets into fine powders followed by dispersion in water with the aid of high concentrations of surfactant. These polyolefin latexes do not blend or mix well with polyacrylics or polymethacrylics (as used herein, “polyacrylics”) and the surfactants made using these formulations could affect the coating coalescence and film formation.
Incorporation of olefin monomers or polymer into the backbone of polyacrylates is difficult. Polyacrylics and polymethacrylics are made by convention emulsion (aqueous) radical polymerization. Olefin monomers or polymers cannot be easily dispersed or emulsified in water and thus cannot be included during the emulsion polymerization of acrylates or methacrylates. Another method to synthesize polyacrylics or polymethacrylics is by controlled radical polymerization. However, due to the radical lifetime of olefinic radicals, control radical polymerization cannot polymerize or copolymerize linear alpha-olefins. Typically, controlled radical polymerization can only random-copolymerize or block-copolymerize styrenics, acrylics, and methacrylics. Thus, what is needed is an improved method of incorporating some level of hydrophobicity in polyacrylics and polyacrylic formulations.
Related publications include WO 2014/047423; EP 1 211 269 A1; and EP 2 479 231.